Salts of bis(fluorosulfonyl)amine are compounds that are useful in various fields such as in battery electrolytes, battery electrolyte additives or materials of electrically conductive coated films (Patent Document 1, Patent Document 2, Patent Document 3). In addition, bis(chlorosulfonyl)amine, by reacting with a fluorinating agent or by carrying out a cation exchange reaction after reacting with a fluorinating agent, can be derived to various salts of bis(fluorosulfonyl)amine, thereby making this a useful compound as well (Patent Document 4, Patent Document 5, Non-Patent Document 1).
A known method for synthesizing bis(chlorosulfonyl)amine consists of mixing sulfamic acid, thionyl chloride and chlorosulfonic acid followed by heating the mixture and allowing to react (Patent Document 3, Patent Document 4, Patent Document 6, Non-Patent Document 2, Non-Patent Document 3).